Réponses

2013-05-07T19:24:21+02:00

A:

(2x-7)(x-4)-(2x-7)(4x+1)=
2x²+8x-7x-28-8x²-2x+28x+7=
-6x²+27x-21

B:

(4x-1)²+(2x-5)(4x+1)=
(16x²-8x+1)+(8x²-2x-20x+5)=
24x²-30x+6

Voilà j'espere t'avoir aidé :-)

2013-05-07T19:48:44+02:00

A = (2x-7)( x+4 -4x -1) = (2x-7)( -3x +3 ) 

B = (4x-1)(4x-1 +2x-5) = (4x-1)( 6x -6 )